German Published Patent Application No. 198 51 667 refers to a basic configuration of a micro-mechanical mirror arrangement, in which a micro-mechanical mirror plate is suspended by one or more torsional beams or beam springs. To allow large deflection angles of the mirror plate, the torsional beams may be required to be thin and long which may be prone to break.
German Published Patent Application No. 199 63 382 and German Published Patent Application No. 199 41 045 refer to a modification which may provide a more robust configuration of the micro-mechanical mirror arrangement. The modification may relieve stress upon the micro-mechanical torsional beams if the micro-mechanical mirror plate is moved in a direction that is vertical to the plane of the micro-mechanical mirror plate, but not if the micro-mechanical mirror plate is moved in a direction that is parallel or “in-plane” with the micro-mechanical mirror plate. To increase the robustness further, the thickness of the micro-mechanical beams may be increased and/or their length may be reduced. However, such changes to the length and thickness may decrease the “freedom of movement” of the micro-mechanical beam.
German Published Patent Application No. 199 63 382 and German Published Patent Application No. 199 41 045 refer to a two parallel beam configuration, as well as the transformation of bending in a vertical direction perpendicular to the surface of the substrate (i.e. the Z-direction) in tension by using a transversal beam. The resulting stiffness of the whole structure may therefore be significantly higher than that for a single spring of the basic configuration.